[PATCH 1/3] vhost: fix virtqueue array size for control queue

[Maxime Coquelin]

When max_queue_pairs is set to VHOST_MAX_QUEUE_PAIRS (128), VDUSE
calculates total_queues as max_queue_pairs * 2 + 1 = 257 to account
for the control queue. However, the virtqueue array was sized as
VHOST_MAX_QUEUE_PAIRS * 2, causing an out-of-bounds array access.

Fix by defining VHOST_MAX_VRING to explicitly account for the control
queue (VHOST_MAX_QUEUE_PAIRS * 2 + 1) and using it for the virtqueue
array size.

Fixes: f0a37cc6a1e2 ("vhost: add multiqueue support to VDUSE")
Cc: stable at dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/vhost/vhost.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index e9e71c1707..ee61f7415e 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -261,8 +261,9 @@ struct vhost_async {
 };
 
 #define VHOST_RECONNECT_VERSION		0x0
-#define VHOST_MAX_VRING			0x100
 #define VHOST_MAX_QUEUE_PAIRS		0x80
+/* Max vring count: 2 per queue pair plus 1 control queue */
+#define VHOST_MAX_VRING			(VHOST_MAX_QUEUE_PAIRS * 2 + 1)
 
 struct __rte_cache_aligned vhost_reconnect_vring {
 	uint16_t last_avail_idx;
@@ -501,7 +502,7 @@ struct __rte_cache_aligned virtio_net {
 
 	int			extbuf;
 	int			linearbuf;
-	struct vhost_virtqueue	*virtqueue[VHOST_MAX_QUEUE_PAIRS * 2];
+	struct vhost_virtqueue	*virtqueue[VHOST_MAX_VRING];
 
 	rte_rwlock_t	iotlb_pending_lock;
 	struct vhost_iotlb_entry *iotlb_pool;
-- 
2.52.0